1. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
Do Now:
Write three interesting facts you observe in our timeline model of the Earth’s history.

2. Life evolved from simple forms to complex forms.
Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
Do Now:
Write three interesting facts you observe in our timeline model of the Earth’s history.
Life evolved from simple forms to complex forms.
In the present there is more biodiversity than in the past.
For most of the Earth’s history life remained as single cell living things.
First, life appeared on water, and then it moved to land and air.
The appearance of humans is very recent on Earth’s history.

3. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
2. Approximately what percentage of the Earth’s history has life been present? 3. For how many years were ONLY single-celled organisms present? 4. If you consider the full history of the Earth, were dinosaurs a recent or ancient group of animals? 5. Did mammals appear before, after, or during the reign of the dinosaurs? 6. Which group, dinosaurs or mammals, existed longer? What event permitted mammals to spread and diversify?
80 percent
2.9 billion years
Dinosaurs was a recent group, if we consider the full history of the Earth
Mammals appeared during the reign of the dinosaurs
Mammals existed longer than dinosaurs
The extinction of the dinosaurs

4. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
8. When did life first leave the water?
9. Arrange the following events in the correct sequence from the oldest to the most recent.
First mammals, Prokaryotic cells, Extinction of dinosaurs, First humans
b) First life on land, Early Primates, Eukaryotic cells, First flowering plants
c) Multicellular life, Fish-like creatures, Single cells with nucleus, Single cells without nucleus
d) First humans, Early Primates, Extinction of dinosaurs, First Ape-like creatures
Life first leave the water 425 million years ago
Prokaryotic cells, first mammals, extinction of dinosaurs, first humans
Eukaryotic cells, first life on land, first flowering plants, Early primates
Single cells without nucleus, single cells with nucleus, multicellular
life, fish-like creatures
Extinction of dinosaurs, first primates, first ape-like creature, first humans

5. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
9. The first life-forms to appear on
Earth were most likely
A) simple single-celled organisms
B) simple multicellular organisms
C) complex single-celled organisms
D) complex multicellular organisms
Information related to the organisms
found on Earth during various
geological time periods is represented
in the chart below.
10. Which statement concerning the first appearance of the organisms over the time period represented in this chart is most likely correct?
A) Life on Earth has changed rapidly.
B) Life on Earth began with complex organisms and changed to more complex organisms.
C) Life on Earth has changed from primitive organisms to more complex organisms.
D) Life on Earth has remained the same

6. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
Read the statements below and mark them as “True” or “False”.
If it is “False” rewrite correctly.
Dinosaurs and humans coexisted (lived in the same period of time) on the Earth.
(True / False)
b) In the present there is more biodiversity than in the past.
c) Life evolved from complex forms to simple forms.
d) For most of the Earth’s history life remained as single cell living things.

7. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution
e) As time goes by, there is a decrease of biodiversity.
(True / False)
f) There is an absence of all life for the first one billion years.
g) First, life appeared on land, and then it moved to water and air.
h) Plants developed on Earth before animals.
The first organism on Earth was most likely some kind of dinosaur.

8. Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
j) Life appeared 1.5 billion years ago.
(True / False)
k) The appearance of humans is very recent on Earth’s history.
l) For most of the history of Earth life remained simple.
m) There is a biodiversity explosion of life 2 billion years ago.
n) There is an absence of all kind of life for the most of the Earth’s history.
o) Life appeared quite early on Earth.

9. Homework Write two paragraphs including:
Objective: Understand the Main Events in the History of Life through a Timeline
Key Words: Evolution, prokaryotic, eukaryotic cell, extinction, simple, complex
Homework
Write two paragraphs including:
A brief description of the history of life in the planet
Three patterns to infer from the life timeline.